Practice Final #4a with steps
brookewenig
To find the angle between v and w, we apply this formula: cos(theta) = (v . w) / (||v|| ||w||). We then rearrange it to get: theta = arccos [ (v . w) / (||v|| ||w||) ] theta = arccos [ -4 / (sqrt(4 + 49 + 1) * sqrt(1 + 1 + 1))] theta = arccos [ -4 / (sqrt(54) * sqrt(3))] theta = arccos [ -4 / (9 * sqrt(2))] theta = arccos [ -2 * sqrt(2)/9)] This yields the same answer as the previous post, but left in unsimplified form since we will not have calculators on the exam.
brookewenig: May 29, 2015, 8:39 p.m.
Sorry about the formatting, it changed my newlines.
dannystapleton: June 1, 2015, 4:32 p.m.
I also got the same answer!
wllmskn: June 3, 2015, 1:30 p.m.
I got the same thing! I don't understand what we're supposed to do in part b though
wllmskn: June 3, 2015, 1:31 p.m.
*how to go about doing it. I know what we're supposed to find